In many complementary metal oxide semiconductor (CMOS) logic operations it is desirable to have high mobility material for both NMOS and PMOS transistors. With silicon (Si) substrates, low electron or hole mobility values limit speed and increase power consumption. High electron and hole mobility substrate materials, such as indium antimonide (InSb) may greatly improve logic performance.
Forming the gate dielectric of CMOS devices from certain high-k dielectric materials can reduce gate leakage. When conventional processes are used to form such transistors, a layer of an oxide of the substrate may form between the high-k dielectric and the substrate. The presence of that oxide layer may unfavorably contribute to the overall electrical thickness of the gate dielectric stack.